Sensor synchronization offline lab validation system

ABSTRACT

The disclosure describes various embodiments of validating data synchronization between an active sensor and a passive sensor. According to an exemplary method of validating sensor synchronization between an active sensor and a passive sensor, a synchronization device receives a first signal from the active sensor, the first signal indicating that the active sensor has transmitted laser points to a measure board. In response to the first signal, the synchronization device transmits a second signal to the passive sensor to trigger the passive sensor to capture an image of the measure board. A synchronization validation application can perform an analysis of the image of the measure board in view of timing of the first signal and second signal to determine whether the passive sensor and the active sensor are synchronized with each other.

TECHNICAL FIELD

Embodiments of the present disclosure relate generally to operatingautonomous vehicles. More particularly, embodiments of the disclosurerelate to sensor data synchronization validation.

BACKGROUND

Vehicles operating in an autonomous mode (e.g., driverless) can relieveoccupants, especially the driver, from some driving-relatedresponsibilities. When operating in an autonomous mode, the vehicle cannavigate to various locations using onboard sensors, allowing thevehicle to travel with minimal human interaction or in some caseswithout any passengers.

The onboard sensors can include active sensor and passive sensors. Anactive sensor, e.g., a light detection and ranging (LiDAR) device, canprovide its own energy source for illumination; whereas a passivesensor, e.g., a camera, can only detect energy that is naturallyavailable. To increase the certainty and precision of estimates of atarget object, data from the active sensors and passive sensors need tobe synchronized into a single description of the target object.

Sensor data synchronization requires the support of softwareapplications and hardware components, which need to be validated beforethey can be used on an autonomous driving vehicle (ADV) in real time.

Although the software applications and hardware components can bevalidated online in an ADV in real time, such online validation requiressubstantial efforts to set up sensors, and may lack the level ofvalidation accuracy and long-term stability tests provided by offlinevalidation equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are illustrated by way of example and notlimitation in the figures of the accompanying drawings in which likereferences indicate similar elements.

FIG. 1 illustrates an example system for validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment.

FIG. 2 further illustrates an example system for validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment.

FIG. 3 illustrates an example process of validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment.

FIG. 4A, FIG. 4B, and FIG. 4C illustrate example validation scenariosaccording to one embodiment.

FIG. 5 illustrates an example process of validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment.

DETAILED DESCRIPTION

Various embodiments and aspects of the disclosures will be describedwith reference to details discussed below, and the accompanying drawingswill illustrate the various embodiments. The following description anddrawings are illustrative of the disclosure and are not to be construedas limiting the disclosure. Numerous specific details are described toprovide a thorough understanding of various embodiments of the presentdisclosure. However, in certain instances, well-known or conventionaldetails are not described in order to provide a concise discussion ofembodiments of the present disclosures.

Reference in the specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin conjunction with the embodiment can be included in at least oneembodiment of the disclosure. The appearances of the phrase “in oneembodiment” in various places in the specification do not necessarilyall refer to the same embodiment.

The disclosure describes various embodiments for validating datasynchronization between an active sensor and a passive sensor. Thedisclosure uses a LiDAR device and a camera for illustration purposes.Some of the features described herein can also be used to validatesensor synchronization between another type of active sensor and anothertype of passive sensor.

According to an exemplary method of validating sensor synchronizationbetween an active sensor and a passive sensor, a synchronization devicereceives a first signal from the active sensor, the first signalindicating that the active sensor has transmitted laser points to ameasure board. In response to the first signal, the synchronizationdevice transmits a second signal to the passive sensor to trigger thepassive sensor to capture an image of the measure board. Asynchronization validation application can perform an analysis of theimage of the measure board in view of timing of the first signal andsecond signal to determine whether the passive sensor and the activesensor are synchronized with each other.

In one embodiment, the synchronization device includes one or moreelectric circuits and one or more software modules for use insynchronizing sensor data from the active sensor and the passive sensor.The synchronized device includes a number of synchronization settings,with each of the synchronization settings specifying a trigger delay forthe passive sensor and a corresponding target area by the active sensoron the measure board. The synchronization settings include a positivetrigger delay, a zero trigger, and a negative trigger delay. The triggerdelay enables a synchronization point between the active sensor and thepassive sensor to fall in the corresponding target area.

In one embodiment, when performing the analysis of the image of themeasure board, the synchronization validation application can performthe operations of determining that the image captures at least a portionof the laser points on the measure board; determining that asynchronization point between the active sensor and the passive sensoris located at a position defined by one of the synchronization settings;and generating an indication that the active sensor and the passivesensor are synchronized.

In another embodiment, when performing the analysis of the image of themeasure board, the synchronization validation application can performthe operations of determining that the image does not capture any laserpoints on the measure board; and generating an indication that theactive sensor and the passive sensor are unsynchronized.

In one embodiment, a validation system can include a measure board, asynchronization device, and a synchronization validation application.The synchronization device includes one or more hardware components(e.g., electric circuits) and one or more software components forsynchronizing data from the active sensor and the passive sensor. Thesynchronization device further includes one or more sensorsynchronization settings for specifying different synchronization pointsbetween the active sensor and the passive sensor. The synchronizationdevice can cause the active sensor to transmit laser signals to themeasure board. In response to the transmission of the laser signals, thesynchronization device can trigger the passive sensor to capture animage of the measure board. The synchronization validation applicationcan analyze the image to determine whether sensor data from the activesensor and the passive sensor are synchronized with each other based onone or more preset synchronization settings.

Embodiments of the disclosure can provide offline laboratorysynchronization validation, with end to end coverage from physicalsensors to synchronization hardware and software. Once validated, thesoftware components and hardware components in the synchronizationdevice can be deployed in an ADV for real-time driving.

Compared with online real-time sensor synchronization validation,embodiments described herein can provide a higher level of validationaccuracy; a shorter turn-around time; and a longer stability test (e.g.,weeks or months) to stress the physical sensors, the synchronizationhardware and the synchronization software.

In one embodiment, the measure board can be a flat-surfaced board, andcan be made of a variety of materials, including wood, cardboard, glassand metal. The camera can be a rolling shutter camera, with modifiedoptical lens and filters to capture laser signals. For example, theinfrared filter of the passive sensor can be removed, and one or moreoptical lens can be added. Further, the configurations of the passivesensor can be modified so that the passive sensor can be controlled andmanaged by the synchronization device.

In one embodiment, an exemplary process of validating datasynchronization between an active sensor and a passive sensor includesthe operations of transmitting, from an active sensor, laser signals toa measure board, the active sensor coupled to a synchronization device;in response to the transmission of the laser signals, triggering, by thesynchronization device, a passive sensor to capture an image of themeasure board; and performing, by a synchronization validationapplication, an analysis of an image of the measure board captured bythe passive sensor to determine whether the passive sensor and theactive sensor are synchronized with each other.

FIG. 1 illustrates an example system 100 for validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment.

As shown in FIG. 1, a measure board 113 can be placed in front of anactive sensor 109 and a passive sensor 111. The measure board 113 can bea flat-surfaced board made of a variety of materials. For example, themeasure board can be a white-colored steel plate. Both the active sensor109 and the passive sensor 111 are connected to a synchronized device102, which includes one or more sensor synchronization hardwarecomponents 105, one or more sensor synchronization software components107, and one or more sensor synchronization settings 108.

In one embodiment, the sensor synchronization hardware components 105can be an integrated circuit that preforms a number of synchronizationfunctions, including providing digital timing signals. The sensorsynchronization software components 107 can add timestamps to measuresfrom different sensors, including the active sensor 109 and the passivesensor 111, based on the digital timing signals and acquisition times ofthe measures; and can synchronize the timestamped measures to the sameclock.

The sensor synchronization software components 107 can also includefunctions for controlling and managing the passive sensor 111, which canbe a rolling shutter camera that does not take a snapshot of the entiremeasure board 113 at a single instant in time but rather by scanningacross the measure board 113 rapidly, either vertically or horizontally.

The passive sensor 111 can be modified so that the passive sensor cancapture fast moving laser points. For example, the infrared filter ofthe passive sensor 111 can be removed, and one or more optical lens canbe added. Further, setting and configurations of the passive sensor 111can be modified and tuned so that the the passive sensor 111 can becontrolled and managed by the management and controlling functions inthe sensor synchronization software components 107. The settings andconfigurations of the passive sensor 111 can also be modified to alignthe image center of the passive sensor 111 with the field of view (FOV)of the active sensor 109.

In one embodiment, each of the sensor synchronization settings 108 candefine a validation scenario. For example, a synchronization setting caninclude a different target area on the measure board 113 for the activesensor 109 and a corresponding trigger delay for the passive sensor 111.The trigger delay would enable a synchronization point between thepassive sensor 111 and the active sensor 109 to fall in the target areaspecified in the synchronization setting. A synchronization point iswhere vertical scan lines of the active sensor 109 are captured on themeasure board 113 by the passive sensor 111, and where the vertical scanlines of the active sensor 109 and the horizontal frame lines of thepassive sensor 111 have the same capture timestamps.

As a rolling shutter camera, the passive sensor 111 can expose an imageframe of the measure board 113 line after line. The number of exposuresequals the number of lines in the image frame. Each frame linerepresents a row of pixel in the image frame. The frame lines can beequally-spaced parallel lines, with a fixed (e.g., 3 milliseconds)offset in between. The passive sensor may also have a trigger delayparameter, which indicates a delay between a given trigger signal andthe image capture. A trigger delay can be a positive, zero, or negative.If a trigger delay is zero, the passive sensor 111 starts to take thefirst frame line of the image of the measure board immediately after thetrigger signal. If the trigger delay is negative, the passive sensor 111can start to capture the first frame line of the image of the measureboard prior to the trigger signal. If the trigger delay is positive, thepassive sensor 111 can start to capture the first frame line of theimage of the measure board after a tine delay as specified by thetrigger delay.

By adjusting the trigger delay of the passive sensor 111 and/or timeoffsets between frame lines, the synchronization device 102 can causethe synchronization point between the active sensor 109 and the passivesensor 111 to fall in a particular target area.

In real-time driving, the active sensor 109 would be mounted on the topof a vehicle, with the FOV of the active sensor 109 aligned with theimage center of the passive sensor 111. When the active sensor 109 isused to detect traffic lights, the target area of the active sensor 109can be above the image center of the passive sensor 111. When the activesensor is used to detect another vehicle, the target area of the activesensor 109 can at the image center of the passive sensor 111. Differenttarget areas of the active sensor 109 and trigger delays of the passivesensor 111 corresponding to the target areas can be stored in the sensorsynchronization settings 108.

As further shown in FIG. 1, a synchronization validation application 103can run on a computer 101 to perform an analysis of images of themeasure board 113 captured by the passive sensor 111. Thesynchronization validation application 103 can examine the images todetermine whether the active sensor 109 and the passive sensor 111 aresynchronized with each other in accordance with the sensorsynchronization settings 108.

In an alternative embodiment, a user can examine the images captured bythe passive sensor 111 and make judgements on whether the active sensor109 and the passive sensor 111 are synchronized with each other based onthe user's knowledge or training.

FIG. 2 further illustrates an example system 200 for validating sensordata synchronization between an active sensor and a passive sensoraccording to one embodiment.

As shown in FIG. 2, the synchronization validation application 103 caninclude a trained neutral network 203 that takes images 201 of themeasure board 113 captured by the passive sensor 111 as inputs, andidentifies a pattern 207. The identified pattern 207 can be comparedwith an expected pattern 205, which is based on a synchronizationsetting in the sensor synchronization settings 108. Based on thecomparison, the synchronization validation application 103 can generatea validation result 209 for display on a graphical user interface 211.

In one embodiment, the measure board 113 can be positioned at a locationso that the passive sensor 111 can has its image center on apredetermined spot on the measure board 113. The image center of thepassive sensor 111 can be visibly marked, for example, using color tape.The expected pattern 205 and the identified pattern 207 can describe aposition of the synchronization point between the active sensor and thepassive sensor in relation to the marked image center on the measureboard 113.

In one embodiment, when the FOV of the active sensor 109 is aligned withthe image center of the passive sensor 111, the synchronization pointbetween the active sensor and the passive sensor on the measure board112 can be at the image center, directly below the image center, ordirectly above the image center. The synchronization point is where thepassive sensor 111 captures the laser points. When the sensorsynchronization feature is disabled, the passive sensor would not beable to capture any laser points. When the sensor synchronizationfeature is enabled, the passive sensor 111 is expected to capture laserpoints on the measure board 113 consistently at a fixed position (i.e.,synchronization point) given a particular trigger delay.

In one embodiment, the sensor synchronization settings 108 can includemultiple synchronization settings corresponding to different validationscenarios, and can be updated with new synchronization settings. Theexample system 200 can run the validations in accordance with the sensorsynchronization settings 108 hundreds of times or thousands of timesover a period of weeks or even months. The long stability test canvalidate the active sensor 108, the passive sensor 111, thesynchronization hardware components 105, and the synchronizationsoftware components 107 with a higher level of accuracy.

FIG. 3 illustrates an example process 300 of validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment. Process 300 may be performed by processing logicwhich may include software, hardware, or a combination thereof. Forexample, process 300 may be performed by the synchronization validationapplication 103, the synchronization device 102, or a combinationthereof.

Referring to FIG. 3, in operation 301, the synchronization feature isenabled on a synchronization device. When the synchronization feature isdisabled, data from an active sensor and a passive sensor will not besynchronized.

In operation 303, in response to the enabling of the synchronizationfeature, the synchronization device selects a synchronization settingfor validation. The synchronization device can include a number ofsynchronization settings, each synchronization setting specifying avalidation scenario. For example, a validation scenario can include atarget area of the active sensor on a measure board and a correspondingtrigger delay for a passive sensor, which would cause a synchronizationpoint between the passive sensor and the active sensor to match thetarget area specified in the synchronization settings. Thesynchronization settings can be created based on historical drivingstatistics collected from a particular segment of a road and a highdefinition map of the road segment.

In operation 305, the synchronization device prompts the active sensorto transmit laser points to a measure board.

In operation 307, in response to the transmission of the laser points,the synchronization device triggers a passive sensor to take an image ofthe measure board after a pre-configured trigger delay specified in thepreviously-selected synchronization setting. Both the active sensor andthe passive sensor are coupled to the synchronization device, whichincludes hardware components and software components for synchronizationdata from different sensors.

In operation 309, a trained neural network model can perform an analysisof the captured image to identify a pattern.

In operation 311, based on the identified pattern, the processing logiccan determine whether the image shows any laser points.

In operation 315, the processing logic determines that the passivesensor does not capture any laser points and generates an indicationthat the active sensor and the passive sensor are unsynchronized.

In operation operation 317, if the passive sensor captures at least aportion of the laser points, the processing logic can determine whetherthe captured laser points are visible on the image at the expectedlocation, e.g., a target area specified by the synchronization settingpreviously selected.

In operation 319, in response to determining that the passive sensorcaptures the laser points at the expected location on the measure board,the processing logic can determine that the active sensor and thepassive sensor are synchronized. The processing logic can subsequentlyselects another synchronization setting for validation.

FIG. 4A, FIG. 4B, and FIG. 4C illustrate example validation scenariosaccording to one embodiment.

In these figures, the measure board 113 can be positioned in front ofthe active sensor 109 and the passive sensor 111. Since the positions ofthe active sensor 109, the passive sensor 111, and the measure board 113are fixed, the image center 403 of the passive sensor 111 is at a fixedlocation 403 on the measure board 113. The FOV of the active sensor 109and the image center of the passive sensor 111 are aligned such that thewhen the trigger delay of the passive sensor is set to zero, thesynchronization point between the passive sensor and the active sensorwould fall on the image center 403 of the passive sensor 111.

FIG. 4A shows an example validation scenario where the active sensor 109and the passive sensor 111 are unsynchronized. Therefore, when laserpoints transmitted from the active sensor 109 reach the measure board113, the passive sensor would not be able to capture them.

FIG. 4B shows another example validation scenario where the activesensor 109 and the passive sensor 111 are synchronized and the triggerdelay of the passive sensor 111 is set to zero. Therefore, the passivesensor 111 can capture laser points 405 at a fixed location. In thisexample, the fixed location is the image center of the passive sensor111 and also the synchronization point between the active sensor 109 andthe passive sensor 111.

FIG. 4C illustrates yet another example validation scenario where theactive sensor 109 and the passive sensor 111 are synchronized and wherethe corresponding synchronization setting specifies a target area abovethe image center 403. In this scenario, the synchronization setting alsospecifies a negative trigger delay that enables the passive sensor 111to capture the laser point at a synchronization point 406.

For example, the synchronization point 406 can be N frame lines abovethe image center 403. If the time offset between two adjacent framelines is M milliseconds, the trigger delay for the passive sensor wouldneed to be set to −N/M milliseconds.

FIG. 5 illustrates an example process 500 of validating sensor datasynchronization between an active sensor and a passive sensor accordingto one embodiment. Process 500 may be performed by processing logicwhich may include software, hardware, or a combination thereof. Forexample, process 500 may be performed by the synchronization validationapplication 103, the synchronization device 102, or a combinationthereof.

Referring back to FIG. 5, in operation 501, the processing logicreceives, from an active sensor, a first signal indicating that theactive sensor has transmitted laser points to a measure board. Inoperation 502, in response to the first signal, the processing logictransmits a second signal to a passive sensor to trigger the passivesensor to capture an image of the measure board. In operation 503, theprocessing logic performs an analysis of the image of the measure boardin view of timing of the first signal and second signal to determinewhether the passive sensor and the active sensor are synchronized witheach other.

Note that some or all of the components as shown and described above maybe implemented in software, hardware, or a combination thereof. Forexample, such components can be implemented as software installed andstored in a persistent storage device, which can be loaded and executedin a memory by a processor (not shown) to carry out the processes oroperations described throughout this application. Alternatively, suchcomponents can be implemented as executable code programmed or embeddedinto dedicated hardware such as an integrated circuit (e.g., anapplication specific IC or ASIC), a digital signal processor (DSP), or afield programmable gate array (FPGA), which can be accessed via acorresponding driver and/or operating system from an application.Furthermore, such components can be implemented as specific hardwarelogic in a processor or processor core as part of an instruction setaccessible by a software component via one or more specificinstructions.

Some portions of the preceding detailed descriptions have been presentedin terms of algorithms and symbolic representations of operations ondata bits within a computer memory. These algorithmic descriptions andrepresentations are the ways used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of operations leading to adesired result. The operations are those requiring physicalmanipulations of physical quantities.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the above discussion, itis appreciated that throughout the description, discussions utilizingterms such as those set forth in the claims below, refer to the actionand processes of a computer system, or similar electronic computingdevice, that manipulates and transforms data represented as physical(electronic) quantities within the computer system's registers andmemories into other data similarly represented as physical quantitieswithin the computer system memories or registers or other suchinformation storage, transmission or display devices.

Embodiments of the disclosure also relate to an apparatus for performingthe operations herein. Such a computer program is stored in anon-transitory computer readable medium. A machine-readable mediumincludes any mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a machine-readable (e.g.,computer-readable) medium includes a machine (e.g., a computer) readablestorage medium (e.g., read only memory (“ROM”), random access memory(“RAM”), magnetic disk storage media, optical storage media, flashmemory devices).

The processes or methods depicted in the preceding figures may beperformed by processing logic that comprises hardware (e.g. circuitry,dedicated logic, etc.), software (e.g., embodied on a non-transitorycomputer readable medium), or a combination of both. Although theprocesses or methods are described above in terms of some sequentialoperations, it should be appreciated that some of the operationsdescribed may be performed in a different order. Moreover, someoperations may be performed in parallel rather than sequentially.

Embodiments of the present disclosure are not described with referenceto any particular programming language. It will be appreciated that avariety of programming languages may be used to implement the teachingsof embodiments of the disclosure as described herein.

In the foregoing specification, embodiments of the disclosure have beendescribed with reference to specific exemplary embodiments thereof. Itwill be evident that various modifications may be made thereto withoutdeparting from the broader spirit and scope of the disclosure as setforth in the following claims. The specification and drawings are,accordingly, to be regarded in an illustrative sense rather than arestrictive sense.

What is claimed is:
 1. A computer-implemented method of validatingsensor data synchronization, comprising: receiving, at a synchronizationdevice from an active sensor, a first signal indicating that the activesensor has transmitted laser points to a measure board; in response tothe first signal, transmitting, by the synchronization device, a secondsignal to a passive sensor to trigger the passive sensor to capture animage of the measure board; and performing, by a synchronizationvalidation application, an analysis of the image of the measure board inview of timing of the first signal and second signal to determinewhether the passive sensor and the active sensor are synchronized witheach other.
 2. The method of claim 1, wherein the synchronization deviceincludes one or more electric circuit boards and one or more softwaremodules to synchronize sensor data from the active sensor and thepassive sensor.
 3. The method of claim 1, wherein the synchronizeddevice includes a plurality of synchronization settings; wherein eachsynchronization setting specifies a trigger delay for the passivesensor, and a corresponding target area by the active sensor on themeasure board; and wherein the trigger delay enables a synchronizationpoint between the active sensor and the passive sensor to fall in thecorresponding target area.
 4. The method of claim 3, wherein theplurality of synchronization settings include a positive trigger delay,a zero trigger, and a negative trigger delay.
 5. The method of claim 3,wherein performing the analysis of the image of the measure boardfurther includes determining that the image captures at least a portionof the laser points on the measure board; determining that asynchronization point between the active sensor and the passive sensoris located at a position defined by one of the plurality ofsynchronization settings; and generating an indication that the activesensor and the passive sensor are synchronized.
 6. The method of claim1, wherein performing the analysis of the image of the measure boardfurther includes determining that the image does not capture any laserpoints on the measure board; and generating an indication that theactive sensor and the passive sensor are unsynchronized.
 7. The methodof claim 1, wherein the passive sensor is a rolling shutter camera, andwherein the passive sensor is light detection and ranging (LiDAR)device.
 8. The method of claim 1, wherein the synchronization validationapplication includes a trained neutral network for performing theanalysis of the image of the measure board.
 9. A non-transitorymachine-readable medium having instructions stored therein, which whenexecuted by a processor, cause the processor to perform operations, theoperations comprising: receiving, at a synchronization device from anactive sensor, a first signal indicating that the active sensor hastransmitted laser points to a measure board; in response to the firstsignal, transmitting, by the synchronization device, a second signal toa passive sensor to trigger the passive sensor to capture an image ofthe measure board; and performing, by a synchronization validationapplication, an analysis of the image of the measure board in view oftiming of the first signal and second signal to determine whether thepassive sensor and the active sensor are synchronized with each other.10. The non-transitory machine-readable medium of claim 9, wherein thesynchronization device includes one or more electric circuit boards andone or more software modules to synchronize sensor data from the activesensor and the passive sensor.
 11. The non-transitory machine-readablemedium of claim 9, wherein the synchronized device includes a pluralityof synchronization settings; wherein each synchronization settingspecifies a trigger delay for the passive sensor, and a correspondingtarget area by the active sensor on the measure board; and wherein thetrigger delay enables a synchronization point between the active sensorand the passive sensor to fall in the corresponding target area.
 12. Thenon-transitory machine-readable medium of claim 11, wherein theplurality of synchronization settings include a positive trigger delay,a zero trigger, and a negative trigger delay.
 13. The non-transitorymachine-readable medium of claim 9, wherein performing the analysis ofthe image of the measure board further includes determining that theimage captures at least a portion of the laser points on the measureboard; determining that a synchronization point between the activesensor and the passive sensor is located at a position defined by one ofthe plurality of synchronization settings; and generating an indicationthat the active sensor and the passive sensor are synchronized.
 14. Thenon-transitory machine-readable medium of claim 9, wherein performingthe analysis of the image of the measure board further includesdetermining that the image does not capture any laser points on themeasure board; and generating an indication that the active sensor andthe passive sensor are unsynchronized.
 15. The non-transitorymachine-readable medium of claim 9, wherein the passive sensor is arolling shutter camera, and wherein the passive sensor is lightdetection and ranging (LiDAR) device.
 16. The non-transitorymachine-readable medium of claim 9, wherein the synchronizationvalidation application includes a trained neutral network for performingthe analysis of the image of the measure board.
 17. A data processingsystem, comprising: a processor; and a memory coupled to the processorto store instructions, which when executed by the processor, cause theprocessor to perform operations, the operations including receiving, ata synchronization device from an active sensor, a first signalindicating that the active sensor has transmitted laser points to ameasure board; in response to the first signal, transmitting, by thesynchronization device, a second signal to a passive sensor to triggerthe passive sensor to capture an image of the measure board; andperforming, by a synchronization validation application, an analysis ofthe image of the measure board in view of timing of the first signal andsecond signal to determine whether the passive sensor and the activesensor are synchronized with each other.
 18. The system of claim 17,wherein the synchronization device includes one or more electric circuitboards and one or more software modules to synchronize sensor data fromthe active sensor and the passive sensor.
 19. The system of claim 17,wherein the synchronized device includes a plurality of synchronizationsettings; wherein each synchronization setting specifies a trigger delayfor the passive sensor, and a corresponding target area by the activesensor on the measure board; and wherein the trigger delay enables asynchronization point between the active sensor and the passive sensorto fall in the corresponding target area.
 20. The system of claim 19,wherein the plurality of synchronization settings include a positivetrigger delay, a zero trigger, and a negative trigger delay.